As the robot technology is getting more and more matured, collaborative operation of multiple robot arms actively moving within a larger range has become possible. To implement the collaborative operation of multiple robot arms, collaborative control must be performed on the robot arms to avoid the robot arms having conflict of tasks and increase the efficiency.
Through the collaborative operation between the operator and the robot arms, the efficiency of the manufacturing process which involves high complexity or requires high flexibility can be increased, but at the same time the operator will face more hazards. Therefore, how to define the robot working space to avoid the operator being hurt by the robot arm during cooperative task has become more and more important to the manufacturing industries.